In the past, the inspection and grading of produce was mainly a manual process which was both labor intensive and time consuming. Attempts to automate the process and alleviate the amount of handling and inaccuracy associated with the human sorting of produce, initially resulted in the use of mechanical sizing units which sorted produce by size, but which still required visual inspection by a human inspector. As automated produce grading technology developed, photosensitive units were provided to sense the color characteristics of produce items as illustrated by U.S. Pat. Nos. 3,750,883, 4,330,062 and 5,090,576. In addition to color sensing, various systems were developed for also sorting products by weight, as illustrated by U.S. Pat. Nos. 5,294,004, 5,267,654 and 4,482,061.
Where both color and weight sensing are involved in a produce sorting system, the problem has been to effectively transport the produce past color sensing stations which will sense all surfaces of each produce item and then to separately transport the produce over weight sensing assemblies to obtain an item by item weight indication. In the past, this operation has been performed by complex conveyor systems which are combined with individual produce item holding units to both transport and rotate each produce item inspected. This results in not only a relatively time consuming process, but also requires the use of complex machinery in prolonged physical contact with the produce items being graded.
In an attempt to eliminate apparatus for rotating an item during inspection, systems have been developed for dropping items from above onto a conveyor and scanning each item as it falls. These systems are not well suited for the inspection of agricultural products which can be bruised or injured upon impact. Also items tend to bounce when dropped from above making their final position on an output conveyor difficult to accurately ascertain, thereby making an item sorting operation difficult to accomplish.